1. Field of the Invention
The multiple embodiments of present invention relate to an antenna device mounted on a vehicle body such as an automobile.
2. Background Art
Conventionally, a variety of antenna devices may be mounted on a vehicle body of an automobile. FIGS. 14 and 15 are views each showing an example of such an antenna device. As depicted, an antenna device 1 is composed of: an antenna main body 2 provided at an upper side of a roof panel R; and a mount nut 10 provided at a lower side of the roof panel R. The antenna main body 2 comprises: an antenna cover 3; an antenna element 4 mounted on the antenna cover 3; a pad section 5 disposed between the antenna cover 3 and the roof panel R; and a base section (not shown) and a substrate 6 provided at the pad section 5. A matching circuit or an amplifier circuit and a duplexer are incorporated in the substrate 6.
A protrusion section 7 is provided on a lower face of the base section as shown in FIG. 15, and is inserted into an antenna mount hole. A through hole is formed at the inside of the protrusion section 7, and an AM/FM coaxial cable 8 for transmitting a signal and a power supply line 9 for supplying power to the substrate 6 are drawn via the through hole.
The mount nut 10 comprises a ground washer 11 and a nut section 12, and the ground washer 11 is assembled to be rotatable with respect to the nut section 12.
In such an antenna device 1, the antenna main body 2 is first mounted on the antenna mount hole of the roof panel R from overhead shown in FIG. 15. At this time, the antenna main body 2 is temporarily locked so as to be immobilized by a temporarily locking claw 7b or the like. Next, the coaxial cable 8 and the power supply line 9 are routed into a through hole of the protrusion section 7 of the pad section 5. Then, the nut section 12 of the mount nut 10 is helically fitted to the screw section 7a formed on an outer periphery face of the protrusion section 7. Further, when the nut section 12 is rotated, a triangle shaped distal end of the ground washer 11 is cut into a lower face side of the roof panel R shown in FIG. 15, and the antenna main body 2 is securely fixed to the roof panel R and is grounded.
Typically, when an antenna base is snapped onto the main body of a vehicle, the antenna base appears to be fully installed, but the bolt or nut has not been driven to provide full compression between the antenna base and the vehicle body, sealing between the antenna base and the vehicle body and grounding of the antenna to the vehicle body. The undesired result of having the bolt or nut not driven while appearing to be fully installed is that a vehicle can be shipped to a customer with the potential for water leakage through the antenna mounting hole. Many times, electrical connections are established through pigtails or a connector which allow for electrical connection when the antenna is partially mated the vehicle body allowing the antenna to electrically function, but the compression and seal have not occurred.